Information Technology Reference
In-Depth Information
Fig. 14 Architecture of the neural network used in the recognition system
The weight update for the output neurons of the network can be determined as:
The error signal at the output of neuron j at iteration n is:
e
j
ð
n
Þ¼
d
j
ð
n
Þ
y
j
ð
n
Þ
ð
1
Þ
The instantaneous value of error for neuron j is
2
e
j
ð
n
Þ
.
eð
Þ
of total error is obtained by summing
2
e
j
ð
Þ
The instantaneous value
n
n
of all
neurons in output layer
2
X
j
2
c
1
e
j
ð
eð
Þ¼
Þ
ð
Þ
n
n
2
where,
includes all neurons in output layer.
Average squared error is given by
'
c
'
N
X
N
n
¼
1
eð
1
e
avg
¼
Þ
ð
Þ
n
3
e
avg
should be mini-
mized. Back-propagation is used to update the weights. Induced local
where, N is the total number of patterns in training set and
field v
j
ð
n
Þ
produced at input of activation function is given by
X
m
v
j
ð
n
Þ¼
w
ji
ð
n
Þ
y
i
ð
n
Þ
ð
4
Þ
i
¼
0
where
'
m
'
is the number of inputs applied to neuron
'
j
'
, so the output can be written
as:
y
j
ð
n
Þ¼/
j
ð
v
j
ð
n
ÞÞ
ð
5
Þ
.
Search WWH ::
Custom Search